Heated Mud Systems: A Solution to Squeezing-Salt Problems

Abstract

Summary Squeezing salts have been a major problem to operating companies worldwide for many years. Most previous solutions to the problem have been aimed at treating the symptoms rather than the cause. Generally, these have been based on running casings capable of withstanding the nonuniform salt loadings because satisfactory cementations have been virtually impossible to achieve because of large washouts in the salt layers. The solution is to use standard oilfield equipment to drill a gauge hole through the squeezing salts, thus providing an optimum cementation environment. Various methods were used to try to resolve the problem; the last was the use of thick-walled casings in conjunction with saturated potassium/ magnesium drilling fluids to reduce salt washout. Unfortunately, washouts still occurred because the muds could not be saturated at the surface to downhole conditions. Now, the drilling fluid is heated on the surface, enabling the required level of salt concentration to be achieved. The heating system, comprising a boiler and heat ex-changer from a conventional well-test package, has been used on eight wells to date. In each case, a gauge hole was drilled through the squeezing-salt sections and, subsequently, successful cementations were performed.